We can sometimes get too academic over tempo markings on rolls.  The
whole point of playing the pedalled player piano is surely to create an
individualistic performance of your own.  For those who found this hard
years ago further aids such as the Metrostyle line, Artistyle stamps
and printed words were originally employed.  The stamps just give
guidance.  There are always going to be a tiny minority of rolls with
clearly totally wrong stamps applied but generally the suggested tempos
provide an acceptable start.

Tempo markings are subjective.  It may seem to you that a tempo of
55 on a particular roll is wrong and far to slow in your opinion.
However, it is perfectly possible that the roll was originally intended
for that slower speed and that it is you who are actually incorrect by
playing the piece faster and assuming the stamping is wrong.  This
works both ways; if you take the view that Joshua Rifkin's very slow
renditions represent the correct speeds for Joplin rags you may assume
that early roll tempos of those rags are incorrect.  It is possible to
perform most pieces of music at widely differing tempos and still
produce musically acceptable performances.

The crucial point is wind motor and tempo governor performance.  These
are simple to rebuild but often difficult to regulate and unforgiving
if not rebuilt and regulated precisely.  If these mechanisms are
given full attention the roll markings will make more musical sense.
A majority of otherwise working player pianos do not possess a reliably
functioning wind motor and tempo governor.  If there is one thing that
will improve an instruments' performance markedly it must surely be the
operation of the thing which governs that musical performance.

Most instruments are calibrated on the basis that "10" equals one foot
of music over the tracker bar in one minute, i.e., "Tempo 80" is 8 feet
of music per minute.  Instruments are usually calibrated with either
70 or 80 being chosen as the reference point.  The tricky part is
adjusting the regulator so the music will slow to 20 and then a dead
halt without creeping whilst at the other end it will rise above 90 and
not just reach a maximum point.  Furthermore, not all roll markings are
standard.  Hupfeld rolls for example are calibrated to a different
scale and a marking of 100 on an Aeolian player does not equate to
100 on a Hupfeld Phonola.

I once saw a roll of "Alte Kameraden" march where some nutcase had
written across the width of the roll, in capital letters, right after
the introduction, "Oi, slow down, mate!"

Writing your own revised tempo markings along the length of rolls is
comically unnecessary.

To conclude, my advice is check your roll motor and tempo governor;
if they are working properly the suggested speeds will become logical.
If merely maintaining strict tempo is your paramount concern then you
should consider enrolling as a student at the Victor Sylvester School
of Strict Tempo Ballroom Dancing or buy a fairground organ.

Sincerely

Adam Ramet